This is such a beautiful sweater! I'm about 125lb, flat chested but broad and I went for the XS. It fits perfectly, nice flow but not baggy. I use it for the trip to yoga class and also casually. It looks great right now with skinny jeans, boots and a nice loop scarf. Its such a wardrobe basic that I got the winter white, black and a tie dye color. I get compliments whenever I wear it. Try it! Your won't be disappointed!